Bill R Posted October 28, 2022 Share Posted October 28, 2022 On my 180 mile trip today, at about mile 150 I lost all power. Engine was still on, no warning light, and all engine specs within range. I pulled over and called Frank McElroy who suggested a loss of turbo. He was spot on. Turbo pressure was zero. But after a few minutes, turbo started to work. I get back on the road, but after a few miles, turbo drops out again. I was able to keep moving as long as I didn't try to push it. I could even maintain 50 mph. For information purposes, I have the 400ISL, with the VGT that is electronically/air actuated. The VGT has an air controlled mechanical actuator mounted on the turbo, see pic below. The air to this is supplied via an electronically controlled valve from the ECM. See pic below. So I am now at my spot where the rig will stay for the next 2 months and I will begin to troubleshoot. If anyone has had this happen, please let me know what you did to troubleshoot. Here are the items I am going to be checking beginning tomorrow. Please chime in on this journey with me. 1) Check air supply to electronic turbo actuator control valve - I can only guess if I am loosing air the turbo will not work. 2) Check for air leaks on line from electronic turbo actuator control valve to the air controlled mechanical actuator on the turbo. Again, loss of air may cause loss of turbo. 3) Test electronic turbo actuator control valve for functionality - this I have no idea how to do. There are three ECM inputs (41,21,28) to this control valve. I did not get any faults, so I am thinking this is not the problem. But if the controller is not working to supply the correct amount of air, it could be. 4) Disassemble the air controlled mechanical actuator on the turbo to see if there are any issues. I am not sure how this mechanical controller works. Any help out there? I have posted a picture below. The electronic actuators mounted on turbos are easy to take off to where you can then move a lever to check the function of the turbo spline movement. But I have searched the internet and Quickserve to see how this air actuated mechanical actuator works and I can not finding anything. 5) If the above does not reveal any problems, then I will pull the turbo and inspect the internals for issues such as sticking splines or damage. However, the more I think about how the turbo was responding, the more I am not thinking it is sticking. There would be turbo power, and maintain, but as soon as I put a higher demand for power the turbo would drop out and take a little bit to recover. Thank you to anyone who has suggestions or confirmation of my plan of action. Link to comment Share on other sites More sharing options...
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